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nditiz1 |
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#1
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Senior Member ![]() ![]() ![]() Group: Members Posts: 1,191 Joined: 26-May 15 From: Mount Airy, Maryland Member No.: 18,763 Region Association: MidAtlantic Region ![]() ![]() |
I recently adjusted my vales .06/.08 and also rebuilt my carbs. They were done separate and driven in between. I'm now noticing a pinging sound coming from the carb barrel on cylinder 3. If I put my hand over the carb throat it makes the sound go away. It is doing this at idle of ~950. I will load a video of the sound. What do you all think?
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DM_2000 |
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#2
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Member ![]() ![]() Group: Members Posts: 217 Joined: 16-August 17 From: PA Member No.: 21,351 Region Association: None ![]() |
In the mean time, are you getting fuel standoff above the # 3 carb inlet? Fuel standoff is when a cloud of fuel vapor is above the carb inlet. This is caused by pressure under the carb rather than vacuum. ( leaking intake valve , sticking valve stem )
When you do the leakdown, actual numbers are less important than where the air is leaking out. I use the hose from my compression gauge after I've removed the check valve and apply ~ 100 PSI not caring about numbers. In your case, compare numbers to the good cylinders. Starting with a new engine and working towards many miles Past rings into the crankcase, normal , gets worse with more miles Past exhaust valve , signs of wear but still acceptable if slight, gets worse with more miles, tight valve adjustment. Past intake valve, this will reduce power / lead to a rough idle and is a sign of trouble that needs fixed. Into the cooling system ( radiator ) needs attention ( yes I know it is AC motor) Leaking between head and cylinder, the AC version of a cylinder to cooling system leak |
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